The Company has various operating leases for real estate and non-real estate items. The non-real estate leases are mainly comprised of automobiles but also include office equipment and other lower-valued items. The Company does not have any finance leases.

Some of the Company’s real estate lease agreements include Company options to either extend and/or terminate the lease. The cost of these options is included in the Company’s right-of-use assets and lease liabilities to the extent that such options are reasonably certain of being exercised. Leases with renewal options allow the Company to extend the lease term typically between 1 to 10 years. When determining the lease term, renewal options reasonably certain of being exercised are included in the lease term. When determining if a renewal option is reasonably certain of being exercised, the Company considers several economic factors, including but not limited to, the significance of leasehold improvements made to the property, whether the physical space is difficult to replace, underlying contractual obligations, and specific characteristics unique to the particular lease that would make it reasonably certain that the Company would exercise such an option.

During the twelve months ended December 31, 2020, the Company recorded $151.5 of additional right-of-use assets of which $133.6 related to three new leases that commenced during the period and three existing leases that were extended during the period.

The Company has existing leases that include variable lease and non-lease components that are not included in the right-of-use asset and lease liability and are reflected as expenses in the periods incurred. Such payments primarily include common area maintenance charges and increases in rent payments that are driven by factors such as future changes in an index (e.g., the Consumer Price Index).

	Years Ended December 31,
	2020		2019
Lease cost:
Operating lease⁽¹⁾	$	29.2	$	23.2
Short-term lease		4.9		4.3
Total lease cost	$	34.1	$	27.5

The weighted average discount rate and the weighted average remaining lease term were 3.0% and 15 years, respectively, as of December 31, 2020. The weighted average discount rate and the weighted average remaining lease term were 3.8% and 4.9 years, respectively, as of December 31, 2019. Operating cash flows used for operating leases for the twelve months ended December 31, 2020 and 2019 were $13.0 and $23.4, respectively. Operating cash flows used for operating leases for the twelve months ended December 31, 2020 was net of $10.3 in tenant improvement allowance receipts.

In 2019, the Company sold two properties in Boulder, Colorado, and three properties in Portland, Oregon, the latter of which were part of sale and leaseback transactions, and leased back the buildings over varying terms into 2021. Total net cash proceeds received for these two transactions were $41.2 and the Company recognized a net gain on the sale of these long-lived assets of $6.8.

Future lease payments under non-cancelable leases as of December 31, 2020 are detailed as follows:

Year Ending December 31,	Amount
2021	$	21.6
2022		20.4
2023		18.3
2024		17.4
2025		16.6
Thereafter		161.7
Total lease payments		256.0
Less: imputed interest		52.8
Total operating lease liabilities	$	203.2

The 2021 payment amount of $21.6 is net of tenant improvement allowances of $6.7. Amounts presented above do not include payments relating to immaterial leases excluded from the balance sheet as well as operating leases with terms of less than twelve months.